gri3-wm/i3bar/src/child.c

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/*
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* vim:ts=4:sw=4:expandtab
*
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* i3bar - an xcb-based status- and ws-bar for i3
* © 2010 Axel Wagner and contributors (see also: LICENSE)
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*
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* child.c: Getting input for the statusline
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*
*/
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdio.h>
#include <stdarg.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
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#include <err.h>
#include <ev.h>
#include <yajl/yajl_common.h>
#include <yajl/yajl_parse.h>
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#include <yajl/yajl_version.h>
#include <yajl/yajl_gen.h>
#include <paths.h>
#include "common.h"
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/* Global variables for child_*() */
i3bar_child child;
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/* stdin- and SIGCHLD-watchers */
ev_io *stdin_io;
ev_child *child_sig;
/* JSON parser for stdin */
yajl_handle parser;
/* JSON generator for stdout */
yajl_gen gen;
typedef struct parser_ctx {
/* True if one of the parsed blocks was urgent */
bool has_urgent;
/* A copy of the last JSON map key. */
char *last_map_key;
/* The current block. Will be filled, then copied and put into the list of
* blocks. */
struct status_block block;
} parser_ctx;
parser_ctx parser_context;
struct statusline_head statusline_head = TAILQ_HEAD_INITIALIZER(statusline_head);
/* Used temporarily while reading a statusline */
struct statusline_head statusline_buffer = TAILQ_HEAD_INITIALIZER(statusline_buffer);
int child_stdin;
/*
* Remove all blocks from the given statusline.
* If free_resources is set, the fields of each status block will be free'd.
*/
static void clear_statusline(struct statusline_head *head, bool free_resources) {
struct status_block *first;
while (!TAILQ_EMPTY(head)) {
first = TAILQ_FIRST(head);
if (free_resources) {
I3STRING_FREE(first->full_text);
I3STRING_FREE(first->short_text);
FREE(first->color);
FREE(first->name);
FREE(first->instance);
FREE(first->min_width_str);
}
TAILQ_REMOVE(head, first, blocks);
free(first);
}
}
static void copy_statusline(struct statusline_head *from, struct statusline_head *to) {
struct status_block *current;
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TAILQ_FOREACH(current, from, blocks) {
struct status_block *new_block = smalloc(sizeof(struct status_block));
memcpy(new_block, current, sizeof(struct status_block));
TAILQ_INSERT_TAIL(to, new_block, blocks);
}
}
/*
* Replaces the statusline in memory with an error message. Pass a format
* string and format parameters as you would in `printf'. The next time
* `draw_bars' is called, the error message text will be drawn on the bar in
* the space allocated for the statusline.
*/
__attribute__((format(printf, 1, 2))) static void set_statusline_error(const char *format, ...) {
clear_statusline(&statusline_head, true);
char *message;
va_list args;
va_start(args, format);
(void)vasprintf(&message, format, args);
struct status_block *err_block = scalloc(sizeof(struct status_block));
err_block->full_text = i3string_from_utf8("Error: ");
err_block->name = sstrdup("error");
err_block->color = sstrdup("red");
err_block->no_separator = true;
struct status_block *message_block = scalloc(sizeof(struct status_block));
message_block->full_text = i3string_from_utf8(message);
message_block->name = sstrdup("error_message");
message_block->color = sstrdup("red");
message_block->no_separator = true;
TAILQ_INSERT_HEAD(&statusline_head, err_block, blocks);
TAILQ_INSERT_TAIL(&statusline_head, message_block, blocks);
FREE(message);
va_end(args);
}
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/*
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* Stop and free() the stdin- and SIGCHLD-watchers
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*
*/
void cleanup(void) {
if (stdin_io != NULL) {
ev_io_stop(main_loop, stdin_io);
FREE(stdin_io);
}
if (child_sig != NULL) {
ev_child_stop(main_loop, child_sig);
FREE(child_sig);
}
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memset(&child, 0, sizeof(i3bar_child));
}
/*
* The start of a new array is the start of a new status line, so we clear all
* previous entries from the buffer.
*/
static int stdin_start_array(void *context) {
// the blocks are still used by statusline_head, so we won't free the
// resources here.
clear_statusline(&statusline_buffer, false);
return 1;
}
/*
* The start of a map is the start of a single block of the status line.
*
*/
static int stdin_start_map(void *context) {
parser_ctx *ctx = context;
memset(&(ctx->block), '\0', sizeof(struct status_block));
/* Default width of the separator block. */
if (config.separator_symbol == NULL)
ctx->block.sep_block_width = logical_px(9);
else
ctx->block.sep_block_width = logical_px(8) + separator_symbol_width;
return 1;
}
static int stdin_map_key(void *context, const unsigned char *key, size_t len) {
parser_ctx *ctx = context;
FREE(ctx->last_map_key);
sasprintf(&(ctx->last_map_key), "%.*s", len, key);
return 1;
}
static int stdin_boolean(void *context, int val) {
parser_ctx *ctx = context;
if (strcasecmp(ctx->last_map_key, "urgent") == 0) {
ctx->block.urgent = val;
return 1;
}
if (strcasecmp(ctx->last_map_key, "separator") == 0) {
ctx->block.no_separator = !val;
return 1;
}
return 1;
}
static int stdin_string(void *context, const unsigned char *val, size_t len) {
parser_ctx *ctx = context;
if (strcasecmp(ctx->last_map_key, "full_text") == 0) {
ctx->block.full_text = i3string_from_markup_with_length((const char *)val, len);
return 1;
}
if (strcasecmp(ctx->last_map_key, "short_text") == 0) {
ctx->block.short_text = i3string_from_markup_with_length((const char *)val, len);
return 1;
}
if (strcasecmp(ctx->last_map_key, "color") == 0) {
sasprintf(&(ctx->block.color), "%.*s", len, val);
return 1;
}
if (strcasecmp(ctx->last_map_key, "markup") == 0) {
ctx->block.is_markup = (len == strlen("pango") && !strncasecmp((const char *)val, "pango", strlen("pango")));
return 1;
}
if (strcasecmp(ctx->last_map_key, "align") == 0) {
if (len == strlen("center") && !strncmp((const char *)val, "center", strlen("center"))) {
ctx->block.align = ALIGN_CENTER;
} else if (len == strlen("right") && !strncmp((const char *)val, "right", strlen("right"))) {
ctx->block.align = ALIGN_RIGHT;
} else {
ctx->block.align = ALIGN_LEFT;
}
return 1;
}
if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
char *copy = (char *)malloc(len + 1);
strncpy(copy, (const char *)val, len);
copy[len] = 0;
ctx->block.min_width_str = copy;
return 1;
}
if (strcasecmp(ctx->last_map_key, "name") == 0) {
char *copy = (char *)malloc(len + 1);
strncpy(copy, (const char *)val, len);
copy[len] = 0;
ctx->block.name = copy;
return 1;
}
if (strcasecmp(ctx->last_map_key, "instance") == 0) {
char *copy = (char *)malloc(len + 1);
strncpy(copy, (const char *)val, len);
copy[len] = 0;
ctx->block.instance = copy;
return 1;
}
return 1;
}
static int stdin_integer(void *context, long long val) {
parser_ctx *ctx = context;
if (strcasecmp(ctx->last_map_key, "min_width") == 0) {
ctx->block.min_width = (uint32_t)val;
return 1;
}
if (strcasecmp(ctx->last_map_key, "separator_block_width") == 0) {
ctx->block.sep_block_width = (uint32_t)val;
return 1;
}
return 1;
}
/*
* When a map is finished, we have an entire status block.
* Move it from the parser's context to the statusline buffer.
*/
static int stdin_end_map(void *context) {
parser_ctx *ctx = context;
struct status_block *new_block = smalloc(sizeof(struct status_block));
memcpy(new_block, &(ctx->block), sizeof(struct status_block));
/* Ensure we have a full_text set, so that when it is missing (or null),
* i3bar doesnt crash and the user gets an annoying message. */
if (!new_block->full_text)
new_block->full_text = i3string_from_utf8("SPEC VIOLATION: full_text is NULL!");
if (new_block->urgent)
ctx->has_urgent = true;
if (new_block->min_width_str) {
i3String *text = i3string_from_utf8(new_block->min_width_str);
i3string_set_markup(text, new_block->is_markup);
new_block->min_width = (uint32_t)predict_text_width(text);
i3string_free(text);
}
i3string_set_markup(new_block->full_text, new_block->is_markup);
if (new_block->short_text != NULL)
i3string_set_markup(new_block->short_text, new_block->is_markup);
TAILQ_INSERT_TAIL(&statusline_buffer, new_block, blocks);
return 1;
}
/*
* When an array is finished, we have an entire statusline.
* Copy it from the buffer to the actual statusline.
*/
static int stdin_end_array(void *context) {
DLOG("copying statusline_buffer to statusline_head\n");
clear_statusline(&statusline_head, true);
copy_statusline(&statusline_buffer, &statusline_head);
DLOG("dumping statusline:\n");
struct status_block *current;
TAILQ_FOREACH(current, &statusline_head, blocks) {
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DLOG("full_text = %s\n", i3string_as_utf8(current->full_text));
DLOG("short_text = %s\n", (current->short_text == NULL ? NULL : i3string_as_utf8(current->short_text)));
DLOG("color = %s\n", current->color);
}
DLOG("end of dump\n");
return 1;
}
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/*
* Helper function to read stdin
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*
* Returns NULL on EOF.
*
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*/
static unsigned char *get_buffer(ev_io *watcher, int *ret_buffer_len) {
int fd = watcher->fd;
int n = 0;
int rec = 0;
int buffer_len = STDIN_CHUNK_SIZE;
unsigned char *buffer = smalloc(buffer_len + 1);
buffer[0] = '\0';
while (1) {
n = read(fd, buffer + rec, buffer_len - rec);
if (n == -1) {
if (errno == EAGAIN) {
/* finish up */
break;
}
ELOG("read() failed!: %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
if (n == 0) {
ELOG("stdin: received EOF\n");
*ret_buffer_len = -1;
return NULL;
}
rec += n;
if (rec == buffer_len) {
buffer_len += STDIN_CHUNK_SIZE;
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buffer = srealloc(buffer, buffer_len);
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}
}
if (*buffer == '\0') {
FREE(buffer);
rec = -1;
}
*ret_buffer_len = rec;
return buffer;
}
static void read_flat_input(char *buffer, int length) {
struct status_block *first = TAILQ_FIRST(&statusline_head);
/* Clear the old buffer if any. */
I3STRING_FREE(first->full_text);
/* Remove the trailing newline and terminate the string at the same
* time. */
if (buffer[length - 1] == '\n' || buffer[length - 1] == '\r')
buffer[length - 1] = '\0';
else
buffer[length] = '\0';
first->full_text = i3string_from_markup(buffer);
}
static bool read_json_input(unsigned char *input, int length) {
yajl_status status = yajl_parse(parser, input, length);
bool has_urgent = false;
if (status != yajl_status_ok) {
char *message = (char *)yajl_get_error(parser, 0, input, length);
/* strip the newline yajl adds to the error message */
if (message[strlen(message) - 1] == '\n')
message[strlen(message) - 1] = '\0';
fprintf(stderr, "[i3bar] Could not parse JSON input (code = %d, message = %s): %.*s\n",
status, message, length, input);
set_statusline_error("Could not parse JSON (%s)", message);
yajl_free_error(parser, (unsigned char *)message);
draw_bars(false);
} else if (parser_context.has_urgent) {
has_urgent = true;
}
return has_urgent;
}
/*
* Callbalk for stdin. We read a line from stdin and store the result
* in statusline
*
*/
void stdin_io_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
int rec;
unsigned char *buffer = get_buffer(watcher, &rec);
if (buffer == NULL)
return;
bool has_urgent = false;
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if (child.version > 0) {
has_urgent = read_json_input(buffer, rec);
} else {
read_flat_input((char *)buffer, rec);
}
free(buffer);
draw_bars(has_urgent);
}
/*
* Callbalk for stdin first line. We read the first line to detect
* whether this is JSON or plain text
*
*/
void stdin_io_first_line_cb(struct ev_loop *loop, ev_io *watcher, int revents) {
int rec;
unsigned char *buffer = get_buffer(watcher, &rec);
if (buffer == NULL)
return;
DLOG("Detecting input type based on buffer *%.*s*\n", rec, buffer);
/* Detect whether this is JSON or plain text. */
unsigned int consumed = 0;
/* At the moment, we dont care for the version. This might change
* in the future, but for now, we just discard it. */
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parse_json_header(&child, buffer, rec, &consumed);
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if (child.version > 0) {
/* If hide-on-modifier is set, we start of by sending the
* child a SIGSTOP, because the bars aren't mapped at start */
if (config.hide_on_modifier) {
stop_child();
}
draw_bars(read_json_input(buffer + consumed, rec - consumed));
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} else {
/* In case of plaintext, we just add a single block and change its
* full_text pointer later. */
struct status_block *new_block = scalloc(sizeof(struct status_block));
TAILQ_INSERT_TAIL(&statusline_head, new_block, blocks);
read_flat_input((char *)buffer, rec);
}
free(buffer);
ev_io_stop(main_loop, stdin_io);
ev_io_init(stdin_io, &stdin_io_cb, STDIN_FILENO, EV_READ);
ev_io_start(main_loop, stdin_io);
}
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/*
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* We received a SIGCHLD, meaning, that the child process terminated.
* We simply free the respective data structures and don't care for input
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* anymore
*
*/
void child_sig_cb(struct ev_loop *loop, ev_child *watcher, int revents) {
int exit_status = WEXITSTATUS(watcher->rstatus);
ELOG("Child (pid: %d) unexpectedly exited with status %d\n",
child.pid,
exit_status);
/* this error is most likely caused by a user giving a nonexecutable or
* nonexistent file, so we will handle those cases separately. */
if (exit_status == 126)
set_statusline_error("status_command is not executable (exit %d)", exit_status);
else if (exit_status == 127)
set_statusline_error("status_command not found or is missing a library dependency (exit %d)", exit_status);
else
set_statusline_error("status_command process exited unexpectedly (exit %d)", exit_status);
cleanup();
draw_bars(false);
}
void child_write_output(void) {
if (child.click_events) {
const unsigned char *output;
size_t size;
ssize_t n;
yajl_gen_get_buf(gen, &output, &size);
n = writeall(child_stdin, output, size);
if (n != -1)
n = writeall(child_stdin, "\n", 1);
yajl_gen_clear(gen);
if (n == -1) {
child.click_events = false;
kill_child();
set_statusline_error("child_write_output failed");
draw_bars(false);
}
}
}
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/*
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* Start a child process with the specified command and reroute stdin.
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* We actually start a $SHELL to execute the command so we don't have to care
* about arguments and such.
*
* If `command' is NULL, such as in the case when no `status_command' is given
* in the bar config, no child will be started.
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*
*/
void start_child(char *command) {
if (command == NULL)
return;
/* Allocate a yajl parser which will be used to parse stdin. */
static yajl_callbacks callbacks = {
.yajl_boolean = stdin_boolean,
.yajl_integer = stdin_integer,
.yajl_string = stdin_string,
.yajl_start_map = stdin_start_map,
.yajl_map_key = stdin_map_key,
.yajl_end_map = stdin_end_map,
.yajl_start_array = stdin_start_array,
.yajl_end_array = stdin_end_array,
};
parser = yajl_alloc(&callbacks, NULL, &parser_context);
gen = yajl_gen_alloc(NULL);
int pipe_in[2]; /* pipe we read from */
int pipe_out[2]; /* pipe we write to */
if (pipe(pipe_in) == -1)
err(EXIT_FAILURE, "pipe(pipe_in)");
if (pipe(pipe_out) == -1)
err(EXIT_FAILURE, "pipe(pipe_out)");
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child.pid = fork();
switch (child.pid) {
case -1:
ELOG("Couldn't fork(): %s\n", strerror(errno));
exit(EXIT_FAILURE);
case 0:
/* Child-process. Reroute streams and start shell */
close(pipe_in[0]);
close(pipe_out[1]);
dup2(pipe_in[1], STDOUT_FILENO);
dup2(pipe_out[0], STDIN_FILENO);
setpgid(child.pid, 0);
execl(_PATH_BSHELL, _PATH_BSHELL, "-c", command, (char *)NULL);
return;
default:
/* Parent-process. Reroute streams */
close(pipe_in[1]);
close(pipe_out[0]);
dup2(pipe_in[0], STDIN_FILENO);
child_stdin = pipe_out[1];
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break;
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}
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/* We set O_NONBLOCK because blocking is evil in event-driven software */
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fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
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stdin_io = smalloc(sizeof(ev_io));
ev_io_init(stdin_io, &stdin_io_first_line_cb, STDIN_FILENO, EV_READ);
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ev_io_start(main_loop, stdin_io);
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/* We must cleanup, if the child unexpectedly terminates */
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child_sig = smalloc(sizeof(ev_child));
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ev_child_init(child_sig, &child_sig_cb, child.pid, 0);
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ev_child_start(main_loop, child_sig);
atexit(kill_child_at_exit);
}
void child_click_events_initialize(void) {
if (!child.click_events_init) {
yajl_gen_array_open(gen);
child_write_output();
child.click_events_init = true;
}
}
void child_click_events_key(const char *key) {
yajl_gen_string(gen, (const unsigned char *)key, strlen(key));
}
/*
* Generates a click event, if enabled.
*
*/
void send_block_clicked(int button, const char *name, const char *instance, int x, int y) {
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if (!child.click_events) {
return;
}
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child_click_events_initialize();
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yajl_gen_map_open(gen);
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if (name) {
child_click_events_key("name");
yajl_gen_string(gen, (const unsigned char *)name, strlen(name));
}
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if (instance) {
child_click_events_key("instance");
yajl_gen_string(gen, (const unsigned char *)instance, strlen(instance));
}
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child_click_events_key("button");
yajl_gen_integer(gen, button);
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child_click_events_key("x");
yajl_gen_integer(gen, x);
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child_click_events_key("y");
yajl_gen_integer(gen, y);
yajl_gen_map_close(gen);
child_write_output();
}
/*
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* kill()s the child process (if any). Called when exit()ing.
*
*/
void kill_child_at_exit(void) {
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if (child.pid > 0) {
if (child.cont_signal > 0 && child.stopped)
killpg(child.pid, child.cont_signal);
killpg(child.pid, SIGTERM);
}
}
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/*
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* kill()s the child process (if existent) and closes and
* free()s the stdin- and SIGCHLD-watchers
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*
*/
void kill_child(void) {
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if (child.pid > 0) {
if (child.cont_signal > 0 && child.stopped)
killpg(child.pid, child.cont_signal);
killpg(child.pid, SIGTERM);
int status;
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waitpid(child.pid, &status, 0);
cleanup();
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}
}
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/*
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* Sends a SIGSTOP to the child process (if existent)
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*
*/
void stop_child(void) {
if (child.stop_signal > 0 && !child.stopped) {
child.stopped = true;
killpg(child.pid, child.stop_signal);
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}
}
/*
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* Sends a SIGCONT to the child process (if existent)
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*
*/
void cont_child(void) {
if (child.cont_signal > 0 && child.stopped) {
child.stopped = false;
killpg(child.pid, child.cont_signal);
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}
}
/*
* Whether or not the child want click events
*
*/
bool child_want_click_events(void) {
return child.click_events;
}